/*****************************************************************************
- * threads.c : threads implementation for the VideoLAN client
+ * threads.c: LibVLC generic thread support
*****************************************************************************
- * Copyright (C) 1999-2008 the VideoLAN team
- * $Id$
+ * Copyright (C) 2009-2012 Rémi Denis-Courmont
*
- * Authors: Jean-Marc Dressler <polux@via.ecp.fr>
- * Samuel Hocevar <sam@zoy.org>
- * Gildas Bazin <gbazin@netcourrier.com>
- * Clément Sténac
- * Rémi Denis-Courmont
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
*
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
-#include <vlc_common.h>
-
-#include "libvlc.h"
-#include <stdarg.h>
#include <assert.h>
-#ifdef HAVE_UNISTD_H
-# include <unistd.h>
-#endif
-#include <signal.h>
-
-#define VLC_THREADS_UNINITIALIZED 0
-#define VLC_THREADS_PENDING 1
-#define VLC_THREADS_ERROR 2
-#define VLC_THREADS_READY 3
-/*****************************************************************************
- * Global mutex for lazy initialization of the threads system
- *****************************************************************************/
-static volatile unsigned i_initializations = 0;
-
-#if defined( LIBVLC_USE_PTHREAD )
-# include <sched.h>
-
-static pthread_mutex_t once_mutex = PTHREAD_MUTEX_INITIALIZER;
-#else
-static vlc_threadvar_t cancel_key;
-#endif
+#include <vlc_common.h>
-/**
- * Global process-wide VLC object.
- * Contains inter-instance data, such as the module cache and global mutexes.
+/*** Global locks ***/
+
+void vlc_global_mutex (unsigned n, bool acquire)
+{
+ static vlc_mutex_t locks[] = {
+ VLC_STATIC_MUTEX,
+ VLC_STATIC_MUTEX,
+ VLC_STATIC_MUTEX,
+ VLC_STATIC_MUTEX,
+ VLC_STATIC_MUTEX,
+ VLC_STATIC_MUTEX,
+ };
+ static_assert (VLC_MAX_MUTEX == (sizeof (locks) / sizeof (locks[0])),
+ "Wrong number of global mutexes");
+ assert (n < (sizeof (locks) / sizeof (locks[0])));
+
+ vlc_mutex_t *lock = locks + n;
+ if (acquire)
+ vlc_mutex_lock (lock);
+ else
+ vlc_mutex_unlock (lock);
+}
+
+#ifdef LIBVLC_NEED_RWLOCK
+/*** Generic read/write locks ***/
+#include <stdlib.h>
+#include <limits.h>
+/* NOTE:
+ * lock->state is a signed long integer:
+ * - The sign bit is set when the lock is held for writing.
+ * - The other bits code the number of times the lock is held for reading.
+ * Consequently:
+ * - The value is negative if and only if the lock is held for writing.
+ * - The value is zero if and only if the lock is not held at all.
*/
-static libvlc_global_data_t *p_root;
+#define READER_MASK LONG_MAX
+#define WRITER_BIT LONG_MIN
-libvlc_global_data_t *vlc_global( void )
+void vlc_rwlock_init (vlc_rwlock_t *lock)
{
- assert( i_initializations > 0 );
- return p_root;
+ vlc_mutex_init (&lock->mutex);
+ vlc_cond_init (&lock->wait);
+ lock->state = 0;
}
-#ifdef HAVE_EXECINFO_H
-# include <execinfo.h>
-#endif
-
-/**
- * Print a backtrace to the standard error for debugging purpose.
- */
-void vlc_trace (const char *fn, const char *file, unsigned line)
+void vlc_rwlock_destroy (vlc_rwlock_t *lock)
{
- fprintf (stderr, "at %s:%u in %s\n", file, line, fn);
- fflush (stderr); /* needed before switch to low-level I/O */
-#ifdef HAVE_BACKTRACE
- void *stack[20];
- int len = backtrace (stack, sizeof (stack) / sizeof (stack[0]));
- backtrace_symbols_fd (stack, len, 2);
-#endif
-#ifndef WIN32
- fsync (2);
-#endif
+ vlc_cond_destroy (&lock->wait);
+ vlc_mutex_destroy (&lock->mutex);
}
-static inline unsigned long vlc_threadid (void)
-{
-#if defined(LIBVLC_USE_PTHREAD)
- union { pthread_t th; unsigned long int i; } v = { };
- v.th = pthread_self ();
- return v.i;
-
-#elif defined (WIN32)
- return GetCurrentThreadId ();
-
-#else
- return 0;
-
-#endif
-}
-
-/*****************************************************************************
- * vlc_thread_fatal: Report an error from the threading layer
- *****************************************************************************
- * This is mostly meant for debugging.
- *****************************************************************************/
-static void
-vlc_thread_fatal (const char *action, int error,
- const char *function, const char *file, unsigned line)
-{
- fprintf (stderr, "LibVLC fatal error %s (%d) in thread %lu ",
- action, error, vlc_threadid ());
- vlc_trace (function, file, line);
-
- /* Sometimes strerror_r() crashes too, so make sure we print an error
- * message before we invoke it */
-#ifdef __GLIBC__
- /* Avoid the strerror_r() prototype brain damage in glibc */
- errno = error;
- fprintf (stderr, " Error message: %m\n");
-#elif !defined (WIN32)
- char buf[1000];
- const char *msg;
-
- switch (strerror_r (error, buf, sizeof (buf)))
- {
- case 0:
- msg = buf;
- break;
- case ERANGE: /* should never happen */
- msg = "unknwon (too big to display)";
- break;
- default:
- msg = "unknown (invalid error number)";
- break;
- }
- fprintf (stderr, " Error message: %s\n", msg);
-#endif
- fflush (stderr);
-
- abort ();
-}
-
-#ifndef NDEBUG
-# define VLC_THREAD_ASSERT( action ) \
- if (val) vlc_thread_fatal (action, val, __func__, __FILE__, __LINE__)
-#else
-# define VLC_THREAD_ASSERT( action ) ((void)val)
-#endif
-
-/**
- * Per-thread cancellation data
- */
-#ifndef LIBVLC_USE_PTHREAD_CANCEL
-typedef struct vlc_cancel_t
-{
- vlc_cleanup_t *cleaners;
- bool killable;
- bool killed;
-} vlc_cancel_t;
-
-# define VLC_CANCEL_INIT { NULL, true, false }
-#endif
-
-/*****************************************************************************
- * vlc_threads_init: initialize threads system
- *****************************************************************************
- * This function requires lazy initialization of a global lock in order to
- * keep the library really thread-safe. Some architectures don't support this
- * and thus do not guarantee the complete reentrancy.
- *****************************************************************************/
-int vlc_threads_init( void )
+void vlc_rwlock_rdlock (vlc_rwlock_t *lock)
{
- int i_ret = VLC_SUCCESS;
-
- /* If we have lazy mutex initialization, use it. Otherwise, we just
- * hope nothing wrong happens. */
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_mutex_lock( &once_mutex );
-#endif
-
- if( i_initializations == 0 )
+ vlc_mutex_lock (&lock->mutex);
+ /* Recursive read-locking is allowed.
+ * Ensure that there is no active writer. */
+ while (lock->state < 0)
{
- p_root = vlc_custom_create( (vlc_object_t *)NULL, sizeof( *p_root ),
- VLC_OBJECT_GENERIC, "root" );
- if( p_root == NULL )
- {
- i_ret = VLC_ENOMEM;
- goto out;
- }
-
- /* We should be safe now. Do all the initialization stuff we want. */
-#ifndef LIBVLC_USE_PTHREAD_CANCEL
- vlc_threadvar_create( &cancel_key, free );
-#endif
+ assert (lock->state == WRITER_BIT);
+ mutex_cleanup_push (&lock->mutex);
+ vlc_cond_wait (&lock->wait, &lock->mutex);
+ vlc_cleanup_pop ();
}
- i_initializations++;
-
-out:
- /* If we have lazy mutex initialization support, unlock the mutex.
- * Otherwize, we are screwed. */
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_mutex_unlock( &once_mutex );
-#endif
-
- return i_ret;
+ if (unlikely(lock->state >= READER_MASK))
+ abort (); /* An overflow is certainly a recursion bug. */
+ lock->state++;
+ vlc_mutex_unlock (&lock->mutex);
}
-/*****************************************************************************
- * vlc_threads_end: stop threads system
- *****************************************************************************
- * FIXME: This function is far from being threadsafe.
- *****************************************************************************/
-void vlc_threads_end( void )
+void vlc_rwlock_wrlock (vlc_rwlock_t *lock)
{
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_mutex_lock( &once_mutex );
-#endif
-
- assert( i_initializations > 0 );
-
- if( i_initializations == 1 )
+ vlc_mutex_lock (&lock->mutex);
+ /* Wait until nobody owns the lock in any way. */
+ while (lock->state != 0)
{
- vlc_object_release( p_root );
-#ifndef LIBVLC_USE_PTHREAD
- vlc_threadvar_delete( &cancel_key );
-#endif
+ mutex_cleanup_push (&lock->mutex);
+ vlc_cond_wait (&lock->wait, &lock->mutex);
+ vlc_cleanup_pop ();
}
- i_initializations--;
-
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_mutex_unlock( &once_mutex );
-#endif
-}
-
-#if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
-/* This is not prototyped under glibc, though it exists. */
-int pthread_mutexattr_setkind_np( pthread_mutexattr_t *attr, int kind );
-#endif
-
-/*****************************************************************************
- * vlc_mutex_init: initialize a mutex
- *****************************************************************************/
-int vlc_mutex_init( vlc_mutex_t *p_mutex )
-{
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_mutexattr_t attr;
- int i_result;
-
- pthread_mutexattr_init( &attr );
-
-# ifndef NDEBUG
- /* Create error-checking mutex to detect problems more easily. */
-# if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
- pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_ERRORCHECK_NP );
-# else
- pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_ERRORCHECK );
-# endif
-# endif
- i_result = pthread_mutex_init( p_mutex, &attr );
- pthread_mutexattr_destroy( &attr );
- return i_result;
-
-#elif defined( WIN32 )
- InitializeCriticalSection (&p_mutex->mutex);
- p_mutex->recursive = false;
- return 0;
-
-#endif
+ lock->state = WRITER_BIT;
+ vlc_mutex_unlock (&lock->mutex);
}
-/*****************************************************************************
- * vlc_mutex_init: initialize a recursive mutex (Do not use)
- *****************************************************************************/
-int vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
+void vlc_rwlock_unlock (vlc_rwlock_t *lock)
{
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_mutexattr_t attr;
- int i_result;
-
- pthread_mutexattr_init( &attr );
-# if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
- pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_RECURSIVE_NP );
-# else
- pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_RECURSIVE );
-# endif
- i_result = pthread_mutex_init( p_mutex, &attr );
- pthread_mutexattr_destroy( &attr );
- return( i_result );
-
-#elif defined( WIN32 )
- InitializeCriticalSection( &p_mutex->mutex );
- p_mutex->owner = 0; /* the error value for GetThreadId()! */
- p_mutex->recursion = 0;
- p_mutex->recursive = true;
- return 0;
-
-#endif
-}
-
-
-/**
- * Destroys a mutex. The mutex must not be locked.
- *
- * @param p_mutex mutex to destroy
- * @return always succeeds
- */
-void vlc_mutex_destroy (vlc_mutex_t *p_mutex)
-{
-#if defined( LIBVLC_USE_PTHREAD )
- int val = pthread_mutex_destroy( p_mutex );
- VLC_THREAD_ASSERT ("destroying mutex");
-
-#elif defined( WIN32 )
- DeleteCriticalSection (&p_mutex->mutex);
-
-#endif
-}
-
-/**
- * Acquires a mutex. If needed, waits for any other thread to release it.
- * Beware of deadlocks when locking multiple mutexes at the same time,
- * or when using mutexes from callbacks.
- *
- * @param p_mutex mutex initialized with vlc_mutex_init() or
- * vlc_mutex_init_recursive()
- */
-void vlc_mutex_lock (vlc_mutex_t *p_mutex)
-{
-#if defined(LIBVLC_USE_PTHREAD)
- int val = pthread_mutex_lock( p_mutex );
- VLC_THREAD_ASSERT ("locking mutex");
-
-#elif defined( WIN32 )
- if (p_mutex->recursive)
- {
- DWORD self = GetCurrentThreadId ();
-
- if ((DWORD)InterlockedCompareExchange (&p_mutex->owner, self,
- self) == self)
- { /* We already locked this recursive mutex */
- p_mutex->recursion++;
- return;
- }
-
- /* We need to lock this recursive mutex */
- EnterCriticalSection (&p_mutex->mutex);
- self = InterlockedExchange (&p_mutex->owner, self);
- assert (self == 0); /* no previous owner */
- return;
- }
- /* Non-recursive mutex */
- EnterCriticalSection (&p_mutex->mutex);
-
-#endif
-}
-
-
-/**
- * Releases a mutex (or crashes if the mutex is not locked by the caller).
- * @param p_mutex mutex locked with vlc_mutex_lock().
- */
-void vlc_mutex_unlock (vlc_mutex_t *p_mutex)
-{
-#if defined(LIBVLC_USE_PTHREAD)
- int val = pthread_mutex_unlock( p_mutex );
- VLC_THREAD_ASSERT ("unlocking mutex");
-
-#elif defined( WIN32 )
- if (p_mutex->recursive)
- {
- if (p_mutex->recursion != 0)
- {
- p_mutex->recursion--;
- return; /* We still own this mutex */
- }
-
- /* We release the mutex */
- InterlockedExchange (&p_mutex->owner, 0);
- /* fall through */
- }
- LeaveCriticalSection (&p_mutex->mutex);
-
-#endif
-}
-
-/*****************************************************************************
- * vlc_cond_init: initialize a condition variable
- *****************************************************************************/
-int vlc_cond_init( vlc_cond_t *p_condvar )
-{
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_condattr_t attr;
- int ret;
-
- ret = pthread_condattr_init (&attr);
- if (ret)
- return ret;
-
-# if !defined (_POSIX_CLOCK_SELECTION)
- /* Fairly outdated POSIX support (that was defined in 2001) */
-# define _POSIX_CLOCK_SELECTION (-1)
-# endif
-# if (_POSIX_CLOCK_SELECTION >= 0)
- /* NOTE: This must be the same clock as the one in mtime.c */
- pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
-# endif
-
- ret = pthread_cond_init (p_condvar, &attr);
- pthread_condattr_destroy (&attr);
- return ret;
-
-#elif defined( WIN32 )
- /* Create a manual-reset event (manual reset is needed for broadcast). */
- *p_condvar = CreateEvent( NULL, TRUE, FALSE, NULL );
- return *p_condvar ? 0 : ENOMEM;
-
-#endif
-}
-
-/**
- * Destroys a condition variable. No threads shall be waiting or signaling the
- * condition.
- * @param p_condvar condition variable to destroy
- */
-void vlc_cond_destroy (vlc_cond_t *p_condvar)
-{
-#if defined( LIBVLC_USE_PTHREAD )
- int val = pthread_cond_destroy( p_condvar );
- VLC_THREAD_ASSERT ("destroying condition");
-
-#elif defined( WIN32 )
- CloseHandle( *p_condvar );
-
-#endif
-}
-
-/**
- * Wakes up one thread waiting on a condition variable, if any.
- * @param p_condvar condition variable
- */
-void vlc_cond_signal (vlc_cond_t *p_condvar)
-{
-#if defined(LIBVLC_USE_PTHREAD)
- int val = pthread_cond_signal( p_condvar );
- VLC_THREAD_ASSERT ("signaling condition variable");
-
-#elif defined( WIN32 )
- /* NOTE: This will cause a broadcast, that is wrong.
- * This will also wake up the next waiting thread if no thread are yet
- * waiting, which is also wrong. However both of these issues are allowed
- * by the provision for spurious wakeups. Better have too many wakeups
- * than too few (= deadlocks). */
- SetEvent (*p_condvar);
-
-#endif
-}
-
-/**
- * Wakes up all threads (if any) waiting on a condition variable.
- * @param p_cond condition variable
- */
-void vlc_cond_broadcast (vlc_cond_t *p_condvar)
-{
-#if defined (LIBVLC_USE_PTHREAD)
- pthread_cond_broadcast (p_condvar);
-
-#elif defined (WIN32)
- SetEvent (*p_condvar);
-
-#endif
-}
-
-#ifdef UNDER_CE
-# warning FIXME
-# define WaitForMultipleObjectsEx(a,b,c) WaitForMultipleObjects(a,b)
-#endif
-
-/**
- * Waits for a condition variable. The calling thread will be suspended until
- * another thread calls vlc_cond_signal() or vlc_cond_broadcast() on the same
- * condition variable, the thread is cancelled with vlc_cancel(), or the
- * system causes a "spurious" unsolicited wake-up.
- *
- * A mutex is needed to wait on a condition variable. It must <b>not</b> be
- * a recursive mutex. Although it is possible to use the same mutex for
- * multiple condition, it is not valid to use different mutexes for the same
- * condition variable at the same time from different threads.
- *
- * In case of thread cancellation, the mutex is always locked before
- * cancellation proceeds.
- *
- * The canonical way to use a condition variable to wait for event foobar is:
- @code
- vlc_mutex_lock (&lock);
- mutex_cleanup_push (&lock); // release the mutex in case of cancellation
-
- while (!foobar)
- vlc_cond_wait (&wait, &lock);
-
- --- foobar is now true, do something about it here --
-
- vlc_cleanup_run (); // release the mutex
- @endcode
- *
- * @param p_condvar condition variable to wait on
- * @param p_mutex mutex which is unlocked while waiting,
- * then locked again when waking up.
- * @param deadline <b>absolute</b> timeout
- *
- * @return 0 if the condition was signaled, an error code in case of timeout.
- */
-void vlc_cond_wait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex)
-{
-#if defined(LIBVLC_USE_PTHREAD)
- int val = pthread_cond_wait( p_condvar, p_mutex );
- VLC_THREAD_ASSERT ("waiting on condition");
-
-#elif defined( WIN32 )
- DWORD result;
-
- assert (!p_mutex->recursive);
- do
- {
- vlc_testcancel ();
- LeaveCriticalSection (&p_mutex->mutex);
- result = WaitForSingleObjectEx (*p_condvar, INFINITE, TRUE);
- EnterCriticalSection (&p_mutex->mutex);
- }
- while (result == WAIT_IO_COMPLETION);
-
- ResetEvent (*p_condvar);
-
-#endif
-}
-
-/**
- * Waits for a condition variable up to a certain date.
- * This works like vlc_cond_wait(), except for the additional timeout.
- *
- * @param p_condvar condition variable to wait on
- * @param p_mutex mutex which is unlocked while waiting,
- * then locked again when waking up.
- * @param deadline <b>absolute</b> timeout
- *
- * @return 0 if the condition was signaled, an error code in case of timeout.
- */
-int vlc_cond_timedwait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex,
- mtime_t deadline)
-{
-#if defined(LIBVLC_USE_PTHREAD)
- lldiv_t d = lldiv( deadline, CLOCK_FREQ );
- struct timespec ts = { d.quot, d.rem * (1000000000 / CLOCK_FREQ) };
-
- int val = pthread_cond_timedwait (p_condvar, p_mutex, &ts);
- if (val != ETIMEDOUT)
- VLC_THREAD_ASSERT ("timed-waiting on condition");
- return val;
-
-#elif defined( WIN32 )
- DWORD result;
-
- assert (!p_mutex->recursive);
- do
- {
- vlc_testcancel ();
-
- mtime_t total = (deadline - mdate ())/1000;
- if( total < 0 )
- total = 0;
-
- DWORD delay = (total > 0x7fffffff) ? 0x7fffffff : total;
- LeaveCriticalSection (&p_mutex->mutex);
- result = WaitForSingleObjectEx (*p_condvar, delay, TRUE);
- EnterCriticalSection (&p_mutex->mutex);
- }
- while (result == WAIT_IO_COMPLETION);
-
- ResetEvent (*p_condvar);
-
- return (result == WAIT_OBJECT_0) ? 0 : ETIMEDOUT;
-
-#endif
-}
-
-/*****************************************************************************
- * vlc_tls_create: create a thread-local variable
- *****************************************************************************/
-int vlc_threadvar_create( vlc_threadvar_t *p_tls, void (*destr) (void *) )
-{
- int i_ret;
-
-#if defined( LIBVLC_USE_PTHREAD )
- i_ret = pthread_key_create( p_tls, destr );
-#elif defined( UNDER_CE )
- i_ret = ENOSYS;
-#elif defined( WIN32 )
- /* FIXME: remember/use the destr() callback and stop leaking whatever */
- *p_tls = TlsAlloc();
- i_ret = (*p_tls == TLS_OUT_OF_INDEXES) ? EAGAIN : 0;
-#else
-# error Unimplemented!
-#endif
- return i_ret;
-}
-
-void vlc_threadvar_delete (vlc_threadvar_t *p_tls)
-{
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_key_delete (*p_tls);
-#elif defined( UNDER_CE )
-#elif defined( WIN32 )
- TlsFree (*p_tls);
-#else
-# error Unimplemented!
-#endif
-}
-
-#if defined (LIBVLC_USE_PTHREAD)
-#elif defined (WIN32)
-static unsigned __stdcall vlc_entry (void *data)
-{
- vlc_cancel_t cancel_data = VLC_CANCEL_INIT;
- vlc_thread_t self = data;
-
- vlc_threadvar_set (&cancel_key, &cancel_data);
- self->data = self->entry (self->data);
- return 0;
-}
-#endif
-
-/**
- * Creates and starts new thread.
- *
- * @param p_handle [OUT] pointer to write the handle of the created thread to
- * @param entry entry point for the thread
- * @param data data parameter given to the entry point
- * @param priority thread priority value
- * @return 0 on success, a standard error code on error.
- */
-int vlc_clone (vlc_thread_t *p_handle, void * (*entry) (void *), void *data,
- int priority)
-{
- int ret;
-
-#if defined( LIBVLC_USE_PTHREAD )
- pthread_attr_t attr;
- pthread_attr_init (&attr);
-
- /* Block the signals that signals interface plugin handles.
- * If the LibVLC caller wants to handle some signals by itself, it should
- * block these before whenever invoking LibVLC. And it must obviously not
- * start the VLC signals interface plugin.
- *
- * LibVLC will normally ignore any interruption caused by an asynchronous
- * signal during a system call. But there may well be some buggy cases
- * where it fails to handle EINTR (bug reports welcome). Some underlying
- * libraries might also not handle EINTR properly.
- */
- sigset_t oldset;
- {
- sigset_t set;
- sigemptyset (&set);
- sigdelset (&set, SIGHUP);
- sigaddset (&set, SIGINT);
- sigaddset (&set, SIGQUIT);
- sigaddset (&set, SIGTERM);
-
- sigaddset (&set, SIGPIPE); /* We don't want this one, really! */
- pthread_sigmask (SIG_BLOCK, &set, &oldset);
- }
- {
- struct sched_param sp = { .sched_priority = priority, };
- int policy;
-
- if (sp.sched_priority <= 0)
- sp.sched_priority += sched_get_priority_max (policy = SCHED_OTHER);
- else
- sp.sched_priority += sched_get_priority_min (policy = SCHED_RR);
-
- pthread_attr_setschedpolicy (&attr, policy);
- pthread_attr_setschedparam (&attr, &sp);
- }
-
- /* The thread stack size.
- * The lower the value, the less address space per thread, the highest
- * maximum simultaneous threads per process. Too low values will cause
- * stack overflows and weird crashes. Set with caution. Also keep in mind
- * that 64-bits platforms consume more stack than 32-bits one.
- *
- * Thanks to on-demand paging, thread stack size only affects address space
- * consumption. In terms of memory, threads only use what they need
- * (rounded up to the page boundary).
- *
- * For example, on Linux i386, the default is 2 mega-bytes, which supports
- * about 320 threads per processes. */
-#define VLC_STACKSIZE (128 * sizeof (void *) * 1024)
-
-#ifdef VLC_STACKSIZE
- ret = pthread_attr_setstacksize (&attr, VLC_STACKSIZE);
- assert (ret == 0); /* fails iif VLC_STACKSIZE is invalid */
-#endif
-
- ret = pthread_create (p_handle, &attr, entry, data);
- pthread_sigmask (SIG_SETMASK, &oldset, NULL);
- pthread_attr_destroy (&attr);
-
-#elif defined( WIN32 ) || defined( UNDER_CE )
- /* When using the MSVCRT C library you have to use the _beginthreadex
- * function instead of CreateThread, otherwise you'll end up with
- * memory leaks and the signal functions not working (see Microsoft
- * Knowledge Base, article 104641) */
- HANDLE hThread;
- vlc_thread_t th = malloc (sizeof (*th));
-
- if (th == NULL)
- return ENOMEM;
-
- th->data = data;
- th->entry = entry;
-#if defined( UNDER_CE )
- hThread = CreateThread (NULL, 0, vlc_entry, th, CREATE_SUSPENDED, NULL);
-#else
- hThread = (HANDLE)(uintptr_t)
- _beginthreadex (NULL, 0, vlc_entry, th, CREATE_SUSPENDED, NULL);
-#endif
-
- if (hThread)
- {
- /* Thread closes the handle when exiting, duplicate it here
- * to be on the safe side when joining. */
- if (!DuplicateHandle (GetCurrentProcess (), hThread,
- GetCurrentProcess (), &th->handle, 0, FALSE,
- DUPLICATE_SAME_ACCESS))
- {
- CloseHandle (hThread);
- free (th);
- return ENOMEM;
- }
-
- ResumeThread (hThread);
- if (priority)
- SetThreadPriority (hThread, priority);
-
- ret = 0;
- *p_handle = th;
+ vlc_mutex_lock (&lock->mutex);
+ if (lock->state < 0)
+ { /* Write unlock */
+ assert (lock->state == WRITER_BIT);
+ /* Let reader and writer compete. OS scheduler decides who wins. */
+ lock->state = 0;
+ vlc_cond_broadcast (&lock->wait);
}
else
- {
- ret = errno;
- free (th);
+ { /* Read unlock */
+ assert (lock->state > 0);
+ /* If there are no readers left, wake up one pending writer. */
+ if (--lock->state == 0)
+ vlc_cond_signal (&lock->wait);
}
-
-#endif
- return ret;
+ vlc_mutex_unlock (&lock->mutex);
}
+#endif /* LIBVLC_NEED_RWLOCK */
-#if defined (WIN32)
-/* APC procedure for thread cancellation */
-static void CALLBACK vlc_cancel_self (ULONG_PTR dummy)
-{
- (void)dummy;
- vlc_control_cancel (VLC_DO_CANCEL);
-}
-#endif
-
-/**
- * Marks a thread as cancelled. Next time the target thread reaches a
- * cancellation point (while not having disabled cancellation), it will
- * run its cancellation cleanup handler, the thread variable destructors, and
- * terminate. vlc_join() must be used afterward regardless of a thread being
- * cancelled or not.
- */
-void vlc_cancel (vlc_thread_t thread_id)
-{
-#if defined (LIBVLC_USE_PTHREAD_CANCEL)
- pthread_cancel (thread_id);
-#elif defined (WIN32)
- QueueUserAPC (vlc_cancel_self, thread_id->handle, 0);
-#else
-# warning vlc_cancel is not implemented!
-#endif
-}
+#ifdef LIBVLC_NEED_SEMAPHORE
+/*** Generic semaphores ***/
+#include <limits.h>
+#include <errno.h>
-/**
- * Waits for a thread to complete (if needed), and destroys it.
- * This is a cancellation point; in case of cancellation, the join does _not_
- * occur.
- *
- * @param handle thread handle
- * @param p_result [OUT] pointer to write the thread return value or NULL
- * @return 0 on success, a standard error code otherwise.
- */
-void vlc_join (vlc_thread_t handle, void **result)
+void vlc_sem_init (vlc_sem_t *sem, unsigned value)
{
-#if defined( LIBVLC_USE_PTHREAD )
- int val = pthread_join (handle, result);
- if (val)
- vlc_thread_fatal ("joining thread", val, __func__, __FILE__, __LINE__);
-
-#elif defined( UNDER_CE ) || defined( WIN32 )
- do
- vlc_testcancel ();
- while (WaitForSingleObjectEx (handle->handle, INFINITE, TRUE)
- == WAIT_IO_COMPLETION);
-
- CloseHandle (handle->handle);
- if (result)
- *result = handle->data;
- free (handle);
-
-#endif
+ vlc_mutex_init (&sem->lock);
+ vlc_cond_init (&sem->wait);
+ sem->value = value;
}
-
-struct vlc_thread_boot
-{
- void * (*entry) (vlc_object_t *);
- vlc_object_t *object;
-};
-
-static void *thread_entry (void *data)
+void vlc_sem_destroy (vlc_sem_t *sem)
{
- vlc_object_t *obj = ((struct vlc_thread_boot *)data)->object;
- void *(*func) (vlc_object_t *) = ((struct vlc_thread_boot *)data)->entry;
-
- free (data);
- msg_Dbg (obj, "thread started");
- func (obj);
- msg_Dbg (obj, "thread ended");
-
- return NULL;
+ vlc_cond_destroy (&sem->wait);
+ vlc_mutex_destroy (&sem->lock);
}
-/*****************************************************************************
- * vlc_thread_create: create a thread, inner version
- *****************************************************************************
- * Note that i_priority is only taken into account on platforms supporting
- * userland real-time priority threads.
- *****************************************************************************/
-int __vlc_thread_create( vlc_object_t *p_this, const char * psz_file, int i_line,
- const char *psz_name, void * ( *func ) ( vlc_object_t * ),
- int i_priority, bool b_wait )
+int vlc_sem_post (vlc_sem_t *sem)
{
- int i_ret;
- vlc_object_internals_t *p_priv = vlc_internals( p_this );
-
- struct vlc_thread_boot *boot = malloc (sizeof (*boot));
- if (boot == NULL)
- return errno;
- boot->entry = func;
- boot->object = p_this;
-
- vlc_object_lock( p_this );
-
- /* Make sure we don't re-create a thread if the object has already one */
- assert( !p_priv->b_thread );
+ int ret = 0;
-#if defined( LIBVLC_USE_PTHREAD )
-#ifndef __APPLE__
- if( config_GetInt( p_this, "rt-priority" ) > 0 )
-#endif
- {
- /* Hack to avoid error msg */
- if( config_GetType( p_this, "rt-offset" ) )
- i_priority += config_GetInt( p_this, "rt-offset" );
- }
-#endif
-
- i_ret = vlc_clone( &p_priv->thread_id, thread_entry, boot, i_priority );
- if( i_ret == 0 )
- {
- if( b_wait )
- {
- msg_Dbg( p_this, "waiting for thread initialization" );
- vlc_object_wait( p_this );
- }
-
- p_priv->b_thread = true;
- msg_Dbg( p_this, "thread %lu (%s) created at priority %d (%s:%d)",
- (unsigned long)p_priv->thread_id, psz_name, i_priority,
- psz_file, i_line );
- }
+ vlc_mutex_lock (&sem->lock);
+ if (likely(sem->value != UINT_MAX))
+ sem->value++;
else
- {
- errno = i_ret;
- msg_Err( p_this, "%s thread could not be created at %s:%d (%m)",
- psz_name, psz_file, i_line );
- }
+ ret = EOVERFLOW;
+ vlc_mutex_unlock (&sem->lock);
+ vlc_cond_signal (&sem->wait);
- vlc_object_unlock( p_this );
- return i_ret;
-}
-
-/*****************************************************************************
- * vlc_thread_set_priority: set the priority of the current thread when we
- * couldn't set it in vlc_thread_create (for instance for the main thread)
- *****************************************************************************/
-int __vlc_thread_set_priority( vlc_object_t *p_this, const char * psz_file,
- int i_line, int i_priority )
-{
- vlc_object_internals_t *p_priv = vlc_internals( p_this );
-
- if( !p_priv->b_thread )
- {
- msg_Err( p_this, "couldn't set priority of non-existent thread" );
- return ESRCH;
- }
-
-#if defined( LIBVLC_USE_PTHREAD )
-# ifndef __APPLE__
- if( config_GetInt( p_this, "rt-priority" ) > 0 )
-# endif
- {
- int i_error, i_policy;
- struct sched_param param;
-
- memset( ¶m, 0, sizeof(struct sched_param) );
- if( config_GetType( p_this, "rt-offset" ) )
- i_priority += config_GetInt( p_this, "rt-offset" );
- if( i_priority <= 0 )
- {
- param.sched_priority = (-1) * i_priority;
- i_policy = SCHED_OTHER;
- }
- else
- {
- param.sched_priority = i_priority;
- i_policy = SCHED_RR;
- }
- if( (i_error = pthread_setschedparam( p_priv->thread_id,
- i_policy, ¶m )) )
- {
- errno = i_error;
- msg_Warn( p_this, "couldn't set thread priority (%s:%d): %m",
- psz_file, i_line );
- i_priority = 0;
- }
- }
-
-#elif defined( WIN32 ) || defined( UNDER_CE )
- VLC_UNUSED( psz_file); VLC_UNUSED( i_line );
-
- if( !SetThreadPriority(p_priv->thread_id->handle, i_priority) )
- {
- msg_Warn( p_this, "couldn't set a faster priority" );
- return 1;
- }
-
-#endif
-
- return 0;
-}
-
-/*****************************************************************************
- * vlc_thread_join: wait until a thread exits, inner version
- *****************************************************************************/
-void __vlc_thread_join( vlc_object_t *p_this )
-{
- vlc_object_internals_t *p_priv = vlc_internals( p_this );
-
-#if defined( LIBVLC_USE_PTHREAD )
- vlc_join (p_priv->thread_id, NULL);
-
-#elif defined( UNDER_CE ) || defined( WIN32 )
- HANDLE hThread;
- FILETIME create_ft, exit_ft, kernel_ft, user_ft;
- int64_t real_time, kernel_time, user_time;
-
- if( ! DuplicateHandle(GetCurrentProcess(),
- p_priv->thread_id->handle,
- GetCurrentProcess(),
- &hThread,
- 0,
- FALSE,
- DUPLICATE_SAME_ACCESS) )
- {
- p_priv->b_thread = false;
- return; /* We have a problem! */
- }
-
- vlc_join( p_priv->thread_id, NULL );
-
- if( GetThreadTimes( hThread, &create_ft, &exit_ft, &kernel_ft, &user_ft ) )
- {
- real_time =
- ((((int64_t)exit_ft.dwHighDateTime)<<32)| exit_ft.dwLowDateTime) -
- ((((int64_t)create_ft.dwHighDateTime)<<32)| create_ft.dwLowDateTime);
- real_time /= 10;
-
- kernel_time =
- ((((int64_t)kernel_ft.dwHighDateTime)<<32)|
- kernel_ft.dwLowDateTime) / 10;
-
- user_time =
- ((((int64_t)user_ft.dwHighDateTime)<<32)|
- user_ft.dwLowDateTime) / 10;
-
- msg_Dbg( p_this, "thread times: "
- "real %"PRId64"m%fs, kernel %"PRId64"m%fs, user %"PRId64"m%fs",
- real_time/60/1000000,
- (double)((real_time%(60*1000000))/1000000.0),
- kernel_time/60/1000000,
- (double)((kernel_time%(60*1000000))/1000000.0),
- user_time/60/1000000,
- (double)((user_time%(60*1000000))/1000000.0) );
- }
- CloseHandle( hThread );
-
-#else
- vlc_join( p_priv->thread_id, NULL );
-
-#endif
-
- p_priv->b_thread = false;
-}
-
-void vlc_thread_cancel (vlc_object_t *obj)
-{
- vlc_object_internals_t *priv = vlc_internals (obj);
-
- if (priv->b_thread)
- vlc_cancel (priv->thread_id);
+ return ret;
}
-void vlc_control_cancel (int cmd, ...)
+void vlc_sem_wait (vlc_sem_t *sem)
{
- /* NOTE: This function only modifies thread-specific data, so there is no
- * need to lock anything. */
-#ifdef LIBVLC_USE_PTHREAD_CANCEL
- (void) cmd;
- assert (0);
-#else
- va_list ap;
-
- vlc_cancel_t *nfo = vlc_threadvar_get (&cancel_key);
- if (nfo == NULL)
- {
-#ifdef WIN32
- /* Main thread - cannot be cancelled anyway */
- return;
-#else
- nfo = malloc (sizeof (*nfo));
- if (nfo == NULL)
- return; /* Uho! Expect problems! */
- *nfo = VLC_CANCEL_INIT;
- vlc_threadvar_set (&cancel_key, nfo);
-#endif
- }
-
- va_start (ap, cmd);
- switch (cmd)
- {
- case VLC_SAVE_CANCEL:
- {
- int *p_state = va_arg (ap, int *);
- *p_state = nfo->killable;
- nfo->killable = false;
- break;
- }
-
- case VLC_RESTORE_CANCEL:
- {
- int state = va_arg (ap, int);
- nfo->killable = state != 0;
- break;
- }
-
- case VLC_TEST_CANCEL:
- if (nfo->killable && nfo->killed)
- {
- for (vlc_cleanup_t *p = nfo->cleaners; p != NULL; p = p->next)
- p->proc (p->data);
-#ifndef WIN32
- free (nfo);
-#endif
-#if defined (LIBVLC_USE_PTHREAD)
- pthread_exit (PTHREAD_CANCELLED);
-#elif defined (WIN32)
- _endthread ();
-#else
-# error Not implemented!
-#endif
- }
- break;
-
- case VLC_DO_CANCEL:
- nfo->killed = true;
- break;
-
- case VLC_CLEANUP_PUSH:
- {
- /* cleaner is a pointer to the caller stack, no need to allocate
- * and copy anything. As a nice side effect, this cannot fail. */
- vlc_cleanup_t *cleaner = va_arg (ap, vlc_cleanup_t *);
- cleaner->next = nfo->cleaners;
- nfo->cleaners = cleaner;
- break;
- }
-
- case VLC_CLEANUP_POP:
- {
- nfo->cleaners = nfo->cleaners->next;
- break;
- }
- }
- va_end (ap);
-#endif
+ vlc_mutex_lock (&sem->lock);
+ mutex_cleanup_push (&sem->lock);
+ while (!sem->value)
+ vlc_cond_wait (&sem->wait, &sem->lock);
+ sem->value--;
+ vlc_cleanup_run ();
}
+#endif /* LIBVLC_NEED_SEMAPHORE */
projects / vlc / blobdiff